1. Field of the Invention
The present invention relates to technology for image printing on printing media by jetting ink drops of each color ink, and more particularly to technology for the printing of high-quality images in which bronzing does not occur.
2. Description of the Related Art
Ink jet printers are widely used as image output devices for machines such as computers. Ink jet printers print color images by forming ink dots in colors such as cyan, magenta, yellow, and black on printing media.
Since ink jet printers form images by jetting ink drops of each color on printing media, when the forming density of the ink dots is high, the jetted ink drops mix on printing media, or the printing paper is caused to swell and crease. In other words, printing paper has a so-called tolerance value for ink, which is the limit beyond which ink dots cannot be formed at higher densities. Thus, various kinds of specialized printing papers are offered which raise the tolerance value of the ink, thereby reducing the likelihood of the occurrence of these problems. By using printing paper specialized for ink jet printers, it is possible to print high-quality images without paper cockling or ink feathering. In addition to these specialized printing papers, specialized papers with even higher performance are offered, such as printing paper on which the surface of the printed image has a gloss finish similar to that of photographs, or printing paper with weatherability on which the printed image does not fade easily.
However, printing images through the use of specialized paper has the problem of worsening of image quality by the occurrence of a phenomenon called xe2x80x9cbronzing.xe2x80x9d Bronzing here refers to a phenomenon in which the quality of the light reflected by the surface of the printing paper changes according to the dye of jetted ink drops condensing on the surface of the printing paper, or according to the print surface having a bronze hue depending on the viewing angle due to the distribution of pigment granularity remaining on the print surface because of the difference in the pigment granularity characteristics of each ink. Techniques have been developed which offer printing paper on which bronzing does not occur easily (see Japanese Patent Laid-open No. 7-214892 or Japanese Patent Laid-open No. 10-217603, among others). Nevertheless, even by using such specialized paper, it is not possible to print high-quality images using the existing wide varieties of printing paper and still avoid bronzing.
The present invention aims to solve the above-mentioned problems found in the conventional art, and it is an object of the present invention to provide a technique for printing high-quality Images without bronzing by using the existing wide variety of printing papers.